Composition to be applied to a surface to increase its wear resistance

ABSTRACT

A coating having high resistance to wear caused by impact, abrasion, erosion and corrosion. A trowelable composition containing high alumina ceramic particles and a co-abrasive filler of smaller particles of inorganic and/or metallic origin in a polymer matrix for application to a surface to be repaired or protected.

O United States Patent 1191 1111 3,876,579 Hallstrom et al. 1 1 Apr. 8, 1975 1 1 COMPOSITION TO BE APPLIED To A 3003.798 10/1961 Sandlin 260/37 EP x SURFACE o INCREASE ITS WEAR 3.033.088 5/1962 Winenwyler 260/37 EP X 3.041.156 6/1962 Rowse et a1. 51/298 RESISTANCE 31081803 4/1963 Bakian..... 51/298 [75] Inventors: James R. Hallstrom, Brookfield; 3.183.633 5/1965 Decker 51/298 X Raymond Hoffman, Fox p 3.205.054 9/1965 Tucker 51/298 R l L w ni Sussex. a" of 3,225,495 12/1965 de Vries 51/298 X Wis 3.277.052 10/1966 Thompson et a1. 260/37 EP X 3.360.391 12/1967 Richtzenhain et a1. 260/37 EP X [73] Assignee: Rexnord Inc., Milwaukee, Wis. 3.383,]91 5/1968 Thomas 51/298 3.469.959 9/1969 Stein 51/298 1221 Hedi 1972 3.502.453 3/1970 Baratta 51/298 N01 3.524.286 8/1970 Wahrer 51/298 Primary Examiner-Donald E. Czaja US. Cl. EP; Ass/31a," E anliner s Person [51] Int. Cl C08g 51/04 Almrney, Agent, or Firm-Kinzer, Plyer. Dorn & [58] Field of Search 260/37 EP; 51/298 MgEac-hran [56] References Cited [57] ABSTRACT UNITED STATES PATENTS A coating having high resistance to wear caused by 2.162.600 6/1939 Bull 51/298 X impact, abrasion. erosion and corrosion. A trowelable 3 9/1940 Bull 51/298 X composition containing high alumina ceramic particles 2 7691199 PZIICh and a co abrasive filler of maller particles of ino c f t 2 32 ganic and/0r metallic origin in a polymer matrix for oep er 2.943.953 7/1960 Daniel 260/37 E? x "ppl'camn surface to be repa'red pmteced' 2.949.351 8/1960 Vigliaturu 51/298 10 Claims, 2 Drawing Figures COMPOSITION TO BE APPLIED TO A SURFACE TO INCREASE ITS WEAR RESISTANCE SUMMARY OF THE INVENTION This invention is concerned with on-the job installation of an abrasive resistant coating and a composition therefore.

An object of this invention is an abrasive resistant coating for application on practically any surface subject to wear regardless of its location.

Another object is such a coating using conventional tools and procedures.

Another object is an abrasive resistant coating which will conform to the surface to which it is applied.

Another object is a wearing composition which may be installed on the job and yet provides a hard wearing surface for areas of severe wear.

Another object is a trowelable composition which quickly hardens to provide a surface having high resistance to abrasion.

Another object is a wear resistant composition which can be applied to irregular surfaces such as those found in cones, elbows. etc.

Another object is an abrasive resistant coating having a secondary abrasive filler of a hardness on the order of that of the material causing the wear.

Another object is an abrasive resistant coating which has a fairly long working life in its mixed stage permitting adequate time to trowel it into difficult to reach or large areas. yet which will cure in a relatively short timev Another object is an abrasive resistant coating that is more resistant to wear than Ni-Hard iron.

Another object is an abrasive resistant coating having a resistance to wear approaching that of ceramic tile.

Another object is an abrasive resistant material that also functions as a corrosion inhibiting coating.

Another object is an abrasive resistant coating which contains alumina ceramic particles.

Another object is an abrasive resistant coating containing alumina ceramic particles which is mixed on the job and in which the particles will not settle out while the composition hardens.

Another object is an abrasive resistant material of the above type that will not settle out in the can.

Other objects may be found in the following specification, claims, and drawings.

FIG. I is a side view. in section, through a typical application in a diagrammatic or schematic representation; and

FIG. 2 is a portion of FIG. 1 on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT This invention is directed to an abrasive resistant surfacing for machinery and wearing surfaces on the job. This is accomplished by use of a composition having high alumina ceramic particles and a co-abrasive filler of smaller particles which are about as hard as the material causing the wear. The particles and filler are contained in components which may be mixed together on the job to provide a substance that can be applied by troweling or similar methods to the surface to be protected or repaired.

The abrasive resistant coating when mixed has a paste-like consistency which enables it to be applied and to conform to any shape such as cones, elbows and other curved surfaces. The paste-like mixture cures rapidly. permitting the surface to be put back into operation quickly. The coating could have a working life of on the order of 30-45 minutes at 68F, which allows ample time to trowel the material onto difficult to reach or large surfaces. It will cure for use in 3-l6 hours at 70F. When necessary. curing time can be reduced by heating metal surfaces to hand warmth or warmer before or after applying the composition. This will reduce the curing or hardening time to. say. approximately l hour.

A composition of this invention may take many different forms. In the drawing, a base or substrate 10 has been shown which may be assumed to be a worn-out part. such as a liner. chute or what-have-you. A coating or composition I2 is superimposed on the surface thereof and. as shown in FIG. 2, in a somewhat schematic or diagrammatic manner. the coating includes a matrix or base substance or bonding agent 14 containing and holding in place large abrasive resistant particles I6 at suitable intervals with smaller abrasive filler particles I8 in the matrix and interposed between and around the larger beads or chips. The matrix material, which may be a polymer. bonds to the surface of the part 10 to be protected and holds the larger abrasive resistant particles 16 in position in relation thereto and in relation to each other and also holds the co-abrasive filler particles 18 in a random dispersion throughout the matrix and in position to take the wear. The matrix itself which may include the resin and a thixotropic agent. when mixed and adhering to the surface. acts as a cushion for the large abrasive resistant particles. Dur ing impact of the material causing wear. such as the various types of ores, sand. gravel. etc., energy is transmitted to the matrix from the particles and is dissipated. This prevents cracking and breaking of the more brittle large abrasive resistant particles.

In such a composition, the co-abrasive or secondary filler particles I8 are of a much smaller size than the primary abrasive resistant particles 16 and these smaller particles fill the voids or interstices between the large abrasive particles. The co-abrasive filler 18 protects the polymer matrix I4 from being worn away from the abrasive resistant particles. As a result, the abrasive resistant particles remain in place in the matrix longer providing a longer wearing surface. The abrasive resistant particles and co-abrasive filler are maintained in suspension in the polymer matrix during mixing and curing operations by means of a thixotropic agent.

While many polymers, abrasive resistant particles. co-abrasive fillers and thixotropic agents may be found suitable for a composition to be used in this invention. a more specific and particularly desirable composition is obtained by the use of high alumina ceramic beads as the abrasive resistant particles. More specifically. the use of metal coated alumina ceramic particles of the type sold by Coors Porcelain Company of Golden. Colorado under the trademark METLX has been found to produce an outstanding abrasive resistant coating. This ceramic is a high alumina type) which has very fine grain (crystal) boundaries to give good abrasive resistance. A coating of metal is placed on the surfaces of ceramic particles. It has been found that polymers and other matrices bond better to the metal coating than they do directly to ceramic. The particles used may be on the order of a fraction of an inch, for example approximately one sixteenth of an inch, in their largest dimension.

A co-abrasive filler found to function particularly well in a wearing composition in accordance with this invention may be silicon carbide, 180 mesh size. However, other fillers may be used as long as they are about as hard as the material being handled, in other words, the material causing the wear on the surface being protected. By way of example, but not of limitation, the following substances may be used as fillers:

Diamond dust, boron carbide, boron nitride, tungsten carbide, alumina ceramic, silica sand, taconite,

etc.

The cost of the wearing composition used in connection with the method of this invention may be reduced by matching the co-abrasive filler to the material causing wear. For example, where sand is the abrasive material causing the wear, silica sand or silica flour may be used as the co-abrasive filler.

The composition of the matrix holding the large abrasive resistant particles in position may vary over a wide range. For example, many types of polymers may be used, such as: epoxide polymers; unsaturated polyester (carboxylate-glycol adduct); a polyurethane; a polyimide or polyamide resin or the like. A particular polymer found to function particularly well as the matrix is an epoxy resin containing a thixotropic agent which resin is cured by means of a mixed polyamine/polyamide curing agent. The thixotropic agent used is a pure CALlDRlA asbestos sold under the designation RG- 144 by Union Carbide Corporation. Other agents might be Bentonite, fumed silica, M-P-A by Baker Caster Oil, polyacrylamide and so forth.

In the composition of this invention, it has been found desirable to provide the large abrasive resistant particles and the co-abrasive filler in both the resin and curing components of the epoxy resin composition. The purpose of doing this is two-fold. First, it provides a mixing ratio between the resin and curing components of approximately 2 to 1 whether the components are measured by weight or volume. Second, it provides thorough wetting of all the abrasive particles and coabrasive filler. A thorough wetting of these materials is difficult to obtain if the materials are provided in only one of the two components.

A specific example of a suitable composition for use in this invention is:

Resin Component Parts by Weight "EPON" Resin 3224. Shell Curing Component Parts by Weight Jefferson AL- 1, Jefferson Chemical Company l0.0 Vanamid 50-40. R. T. Vanderbilt Company 10.0 Asbestos, "RG- l44". Union Carbide Corporation 2.0 Silicon Carbide, 180 X, Simonds Abrasive Div.. The Wallace Murray Corp. 21.7

-Continued Coors METLX" Pellets in this example the resin may be supplied in one can and the curing agent in another, the two being sold together with the resin can being, for example, a l-gallon container and the curing components being in a onehalf-gallon can. This is merely an example and it should be understood that any suitable sizes could be used depending upon the needs of the customer and the amount of material to be used in an application. But a l-gallon can for the resin and the one-half-gallon can for the curing agent has been found convenient. In such a situation a proportion of the amounts would be emptied from each and thoroughly mixed before application to the surface to be protected. And, if all of the resin and curing agents in the two-can kit are not used at once, the cans may be sealed up and used later.

The above example, when mixed, applied, and cured, has the following characteristics:

Tensile Strength 4,000 psi Compressive Strength 15,000 psi Heat Deflection Temperature [95F Lap Shear Strength 2,000 psi Gel Time 90 min. Working Time 30 min. at F.

Another example of a suitable composition is as follows:

Resin Component Parts by Weight Curing Component Parts by Weight Jefferson AL- 1 Jefferson Chemical Company 10.0 Versamid 140, General Mills 10.0 Asbestos, "RC-144, Union Carbide Corporation 1.0 Silicon Carbide, I X, Simonds Abrasive Div. The Wallace Murray Corp. 21.7 Coors METLX" Pellets 70.0

The above composition is believed to have the advantage of better viscosity control.

Another example of a suitable composition is as follows:

Resin Components Parts by Weight EPON 8280, Shell Chemical Corporation 50.0 Asbestos, "RG-l44, Union Carbide Corporation 2.5

TiO,, "TTTANO National Continued Resin Components Parts by Weight Lead Co. L5

Silicon Carbide. I80 X. Simonds This example is believed to have the advantage of longer term shelf stability and would be suitable for uses or applications that require such.

Another example is as follows:

Resin Components Parts By Weight Dow DER 330, Dow Chemical l00.0 Silicon Carbide. I80 X. Simonds Abrasive Div.. The Wallace Murray Corp. 90.0 Coors METLX" Pellets 400.0 Trimelltic Anhydride, Amoco Chemical Company 500 It will be noted that this last example is not a twocomponent composition but rather only one. The composition of this example can be suitably packaged and applied at the point of use and then cured or hardened by heat. For example, after it is applied, it might be cured for two hours at about 250F. followed by an additional, say, 6-hour cure at 350F.

In the above examples it will be noted that the large particles and co-abrasive filler are in a ratio of on the order of 4 to I, while the particles (both large particles and co-abrasive filler) and matrix (resin, curing agent, etc.) are in a ratio on the order of 3 to I.

In certain situations. two parts of Stannous Octoate, supplied by the National Lead Company, could be added to the single component example to reduce the curing time to something on the order of five minutes at 300F.

The wearing composition may be applied or used on any one of a number of parts or surfaces. Good examples are feed chutes, buckets. hoppers, feed plates, pipe and elbows. side plates, diverter plates, discharge chutes and skirts, sand slinger, and the feed spout of grinding mills. It might also be used on trunnion liners, pump casing, return idlers, screens, dust collectors and cyclones and the like. The above are merely examples and it should be understood that other applications are important, such as the hard surfacing of classifier flights and shoes, the drums of cement trucks, fan blades, the surfacing of pan feeders, cobbler repulp circulators, the buckets and teeth of front end loaders, and so forth.

The large abrasive resistant particles have been stated as being high alumina ceramic particles, but a number of other particles could be used, such as boron nitride, tungsten carbide, silicon carbide, boron carbide and the like.

The large particles have been shown as generally round or spherical. But, in certain situations, chips might be used. Round particles may be used for a trowelable mix, but in certain applications, chips might be used. For example, if the composition is to be applied or cast, chips would not be objectionable and they might be less expensive. In certain situations, chips could be used in a trowelable mixture. This is particularly true in a casting system where different beads would be appropriate.

The examples both as to time and temperature given hereinabove are merely for purposes of description. The curing time is flexible and can be varied by modifying the formula somewhat to fit or suit any particular application. The same is true of curing temperature.

I claim:

1. A trowelable wearing composition for on-the-job application to a surface to provide a wearing surface having more resistance to wear caused by impact, abrasion, erosion or corrosion than NiHard iron, including a matrix composed of an uncured curable crosslinkable thermosetting resin, a curing agent for the resin and a thixotropic agent, large abrasion resistant ceramic particles on the order of one-sixteenth inch in their largest dimension, much smaller co-abrasion resistant filler particles on the order of 180 mesh size and of a hardness on the order of that of the material causing the wear dispersed in rather random fashion among the large particles when applied, the ceramic and filler particles being in a ratio on the order of 4 to l by weight, and the particles and matrix being in a ratio on the order of 3 to l by weight.

2. The composition of claim I further characterized in that the large abrasion resistant particles are metal coated alumina ceramic particles.

3. The composition of claim 1 further characterized in that the large ceramic particles are essentially spherical beads.

4. The composition of claim I further characterized in that the co-abrasion resistant filler is silicon carbide.

5. The composition of claim 1 further characterizied in that the thermosetting resin is an epoxy resin.

6. A curable resin composition for on-the-job application to a surface to provide a wearing surface having more resistance to wear than NiHard iron, a unitary system including a container of a certain amount of the uncured resin with large abrasion resistant ceramic particles on the order of one-sixteenth inch in their largest dimension and much smaller co-abrasion resistant filler particles on the order of I mesh size therethrough and of a hardness on the order of that of the material causing the wear, and a separate container with a proportionate amount of a curing agent and with large abrasion resistant ceramic particles on the order of one-sixteenth inch in their largest dimension and much smaller co-abrasion resistant filer particles on the order of I80 mesh size therethrough whereby the contents of both containers are capable of mixing readily by the existence of large and much smaller abrasive particles in each container, the ceramic and filler particles being in a ratio on the order of 4 to I by weight and the particles and resin plus curing agent being in a ratio on the order of 3 to l by weight when the contents of both containers are combined.

7 8 7. The composition of claim 6 further characterized in that the smaller co-abrasion resistant filler particles in that the large abrasion resistant ceramic particles are are Silicon carbide metal coated alumina ceramic particles.

8. The composition of claim 6 further characterized in that the large ceramic particles are spherical beads. 9. The composition of claim 6 further characterized 10. The composition of claim 6 further characterized in that the resin is an epoxy resin.

ii IR l 

1. A TROWELABLE WEARING COMPOSITION FOR ON-THE-JOB APPLICATION TO A SURFACE TO PROVIDE A WEARING SURFACE HAVING MORE RESISTANCE TO WEAR CAUSED BY IMPACT, ABRASION, EROSION OR CORROSION THAN NIHARD IRON, INCLUDING A MATRIX COMPOSED OF AN UNCURED CURABLE CROSSLINKABLE THERMOSETTING RESIN, A CURING AGENT FOR THE RESIN AND A THIXOTROPIC AGENT, LARGE ABRASION RESISTANT CERAMIC PARTICLES ON THE ORDER OF ONE-SIXTEENTH INCH IN THEIR LARGEST DIMENSION, MUCH SMALLER CO-ABRASION RESISTANT FILLER PARTICLES ON THE ORDER OF 180 MESH SIZE AND OF A HARDNESS ON THE ORDER OF THAT OF THE MATERIAL CAUSING THE WEAR DISPERSED IN RATHER RANDOM FASION AMONG THE LARGE PARTICLES WHEN APPLIED, THE CERAMIC AND FILLER PARTICLES BEING IN A RATIO OF THE ORDER OF 4 TO 1 BY WEIGHT, AND THE PARTICLES AND MATRIX BEING IN A RATIO ON THE ORDER OF 3 TO 1 BY WEIGHT.
 2. The composition of claim 1 further characterized in that the large abrasion resistant particles are metal coated alumina ceramic particles.
 3. The composition of claim 1 further characterized in that the large ceramic particles are essentially spherical beads.
 4. The composition of claim 1 further characterized in that the co-abrasion resistant filler is silicon carbide.
 5. The composition of claim 1 further characterizied in that the thermosetting resin is an epoxy resin.
 6. A curable resin composition for on-the-job application to a surface to provide a wearing surface having more resistance to wear than NiHard iron, a unitary system including a container of a certain amount of the uncured resin with large abrasion resistant ceramic particles on the order of one-sixteenth inch in their largest dimension and much smaller co-abrasion resistant filler particles on the order of 180 mesh size therethrough and of a hardness on the order of that of the material causing the wear, and a separate container with a proportionate amount of a curing agent and with large abrasion resistant ceramic particles on the order of one-sixteenth inch in their largest dimension and much smaller co-abrasion resistant filer particles on the order of 180 mesh size therethrough whereby the contents of both containers are capable of mixing readily by the existence of large and much smaller abrasive particles in each container, the ceramic and filler particles being in a ratio on the order of 4 to 1 by weight and the particles and resin plus curing agent being in a ratio on the order of 3 to 1 by weight when the contents of both containers are combined.
 7. The composition of claim 6 further characterized in that the large abrasion resistant ceramic particles are metal coated alumina ceramic particles.
 8. The composition of claim 6 further characterized in that the large ceramic particles are spherical beads.
 9. The composition of claim 6 further characterized in that the smaller co-abrasion resistant filler particles are silicon carbide.
 10. The composition of claim 6 further characterized in that the resin is an epoxy resin. 